Social: Social introversion is the closest to the commonly held understanding of introversion, in that it’s a preference for socializing with small groups instead of large ones. Or sometimes, it’s a preference for no group at all — solitude is often preferable for those who score high in social introversion. “They prefer to stay home with a book or a computer, or to stick to small gatherings with close friends, as opposed to attending large parties with many strangers,” Cheek said. But it’s different from shyness, in that there’s no anxiety driving the preference for solitude or small groups.

I took the quiz at the bottom of the article and I’m a mix of roughly equal parts social, restrained, and anxious introversion with a dash of thinking.